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1、轮机工程（MarineEngineering）Newquestionssupplement1,(C)willallowthepumpsuctionvacuumisincreased:A.reducesatmosphericpressure,B.increasespumppressuredrop,C.reducesliquiddensity,andD.increasesliquidtemperature2,(C)willmakethepumpsuctionvacuumisreduced:A.increasestheatmosphericp
2、ressureB.,reducesthepumppressuredrop,C.increasestheliquiddensityD.,reducestheliquidtemperature3,(D)centrifugalpumpinpracticalwork,whenthepumpflowislessthanthedesignflowrate,therelativevelocityoftheliquidbetweenthetwoblades:A.willincreasetheB.willreduceC.forthewatersurfac
3、eincrease,thebackwaterreducesD.,thewaterleveldecreasesandthebacksurfaceincreases4,(C)centrifugalpumpinactualwork,whenthepumpflowisgreaterthanthedesignflowrate,therelativevelocitybetweenthetwobladesliquid:A.willincrease,B.willreduceC.,increasethewaterlevel,reducethebackwa
4、tersurface,reducethewaterlevelandincreasethewaterlevel5,(A)toobtainlargercentrifugalpumphead,theimpossiblewayis:A.increasetheimpellerexit,A2,B.,reducetheimpellerexit,A2,C.,increasetheimpellerdiameter,D.,increasethespeed6,(B)toobtainalargercentrifugalpumphead,thepossiblew
5、ayis:A.toimprovetheimpellerexit,A2B.,reducingtheimpellerexitA2C.,reducingimpellerouterdiameterD.,reducingspeed7,(D)whenthecentrifugalpumpforliquidviscosityincreases,_____willnotincrease.A.flowresistance,B.disk,frictionloss,C.,frictionloss,D.,impactloss8,(B)whenthecentrif
6、ugalpumpforliquidviscosityincreases,_____losswillincrease.A.impact,B.disk,frictionloss,C.leakage,D.vortex9,(A)volutecentrifugalpumps,whentheflowisgreaterthantheratedflow,theliquidpressurechangesinthepumpfor:A.fromthepumptonguetotheexpansionpipegraduallydecline,B.fromthep
7、umptonguetotheexpansiontubegraduallyincreased,C.,D.isnotnecessarily10,(B)volutecentrifugalpump,whenitsflowrateislessthantheratedflow,theliquidpressurechangelawis:A.fromthepumptonguetotheexpansionpipegraduallydecline,B.fromthepumptonguetotheexpansiontubegraduallyincreased
8、,C.,D.isnotnecessarily11,(A)whenthespecificspeedis10~40,therotarypumpefficiency_____centrifugalpump.A.i
